Torsional detuners or dampers have been used for many years in motor vehicles and are most often disposed between an engine, such as an internal combustion engine, and a transmission. The torsional detuners are typically connected to the flywheel of the engine and the input shaft of the transmission. A torsional detuner operates to reduce or eliminate vibrations that have developed in the crankshaft of the engine. The explosive forces acting on the pistons typically create these vibrations, which thereafter propagate through the crankshaft. At certain engine speeds, the vibration is more noticeable and can be irritating to an operator and, over time, such vibrations may damage the crankshaft itself.
Conventional vibration dampening devices employ detuners having energy storing elements. Typically, these energy storing elements are located on the periphery of the flywheel and include coil springs or a rubber member. Additional storage elements act in an axial direction, relative to the rotation of the flywheel, and cooperate with friction pads or linings to produce friction hysteresis.
While conventional vibration detuners achieve their intended purpose, problems still exist. For example, there are space constraints for packaging the torsional detuners. Further, conventional rubber detuners have a high internal hysteresis that can cause detuner failure due to heat. Moreover, the rubber used in conventional detuners becomes stiffer over time, and the increased stiffness, combined with high operating frequencies, can lead to transmission failure. In addition, it is well known that the compression spring-type detuners used today have inherent wear problems that cause premature failure.
Therefore, a need exists for a vibration detuner that is easily packaged, and withstands the heat and vibration that exists in the powertrain environment. The new improved detuner design should be highly space efficient, easily assembled to the driveline, have a low internal hysteresis and a substantially constant spring rate over time.